Self-stabilizing aeroplane structure.



M. R. WOLFARD. SELF STABILIZING AEROPLANE STRUCTURE.

APPLICATION FILED APR. 10. WW.

Patented Apr. 15,1919.

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AENT orrrcn.

MERL a; woLrAnn, or cnmmarnen, MASSACHUSETTS.

SELFSTABILIZIN G AERO PLAN'E STRUCTURE.

Application filed April 10, 1918. Serial No. 227,688.

lowing 1s a specification.

- This invention relates to improvements in aeroplanes. It relates more specifically to a self-stabilizing aeroplane structure, and in: cludes the adaptation of this structure for use as a gliding, or flying torpedo. By virtue of the inherent stability of this structure it is practically impossible for air currents to overturn the torpedo while in flight; therefore, if it be equipped with an elevator and a rudder, and both of these adapted to be controlled by wireless, then the torpedo can be directed precisely into the desired objective.

The fundamental structural and stabilizing feature of thisinvention, epigrammatically stated, is a covered V-wing arrangement, in which the wing tips of the'V are directly attachedto the cover, thereby securmg novel and effective stabilizing characteristics in combination with desirable flexibility of structure and extreme lightness of" construction.

These stabilizing characteristics and other features of the invention are illustrated in the annexed drawings and more fully described in the following specification.

Referring to the drawings:

Figure 1 is an embodiment of the inventlon, shown in perspective, adapted to be gliding torpedo.

Figs. 2 to 5, inclusive, show some of the structural variations which maybe made in wing arrangements within the scope of the Invention. These are also shown in per.-

. spective. p Fig. 6 illustrates the method of using the 45. acteristicsof its path.

gliding torpedo, and shows the salient charsi 7 is a series of di grams intended i to illustrate 'stabilizing features of theinyention;

I The term V, V-win arrangement or V- structure, as used in t e'specificaltion and claims ofthisinventiom is intended to include any areoplane structure in whichthe wings extend outward and upward in such manner that a tilting of the aeroplane, sidewise, increases the wing surface exposed to Specification of Letters Patent.

action of the wind normal to Patented Apr. 15, 1919.

upward reaction or lift on one side of the center of gravity (said wing surface being the one which 1s depressed by the tilting action) irrespective of the geometric con tour of the wings themselves.

In the drawings the numeral 1 designates wing structures extendin outward and upward and will usually referred to as simply the sides of the V; '2 is attached in any convenient manner to tips of the sides of the V; 3 is a longitudinal web a cover wing extending from the central portion of the V v to the central portion of the cover wing, and 3 is an elastic portion secured in this same web whereby it may elongate vertically' when the upward pressure on the cover wing becomes abnormally high; 4 is a rud 4 der for steerino the aeroplane to the right .Or left' 5 is a horizontal rudder, or, as it is usually termed, an elevator for causing the aeroplane to ascend or descend. In Fig. 1 side keels 6 are shown, whichstifl'en the structure longitudinally and appear to steadythe flight. These may be extended to support the elevator, as indicated 7 is.

a keel structure extending backwand below the horizontal projection of the bottom of the V, as indicated in Figs. 4 and v5; 8 represents the position of the bomb when the areoplane is adapted foruse as a' glidin torpedo.

fihe'leading stabilizing feature of th1s invention is the cover win 2,. andsome of its' 'characteristics seem to e accounted for by assuming, in so far as sudden eddles, Whirlpools and gusts are concerned, that the pressures exerted within the lnclosed space between the sides of the V and the cover are balanced, then' the actlon of the external forces caused by a side wind ma be-analyzed as follows: In Fig. 7, A 1n lcates the ordinary- V structure in normal posltlon;

B is the same tilted sidewise; C shows a' plane cover, D a curved arch-like cover, and.

E -an angular arch-like cover; these last three are all shown in the tilted ilosition also, and the small arrows indicate t the surface a, and decreased on the surface I), and, furthermore, both of these tend to e resultant the surfaces. In B the density of the air is increased 01.1

overturn the aeroplane; In C the forces act ingronc replace those which acted, before 'on .b, and the sum total. of the'se'has aless overturning tendency than before; in other words, the cover has a. stabilizing laendency.

In D and E this stabilizing tendency is even more pronounced, and indeed, a positiverighting tendency may be realized from the cover considered alone, if the altitude of the arch is not too great. This should be evident when one considers the fact that if i the altitude of the arch is too great, the

. when properly proportioned and supported,

has very effective stabilizing characteristics. It might be added here that if we assume a steady side wind to continue to move with the same velocity inside the covered V as outside, then 'the righti tendency of the arched cover considered a one still persists,

and is increased approximatelytwo-fold; but the plane cover theoretically ceases to have any stabilizin tendency save such as may be due to its iplane efl'ect when considered in conjunction with the V itself.'- If,

. however, the lane cover wing does not pro- .ject apprecia 1y beyond its junction at either end with the tips of the V, e. if projecting wing tips are avoided, and if the mechanism as a whole is properly proportioned, then a very considerable stabilizing effect can be realized, practically.

bility, the

It appears that for extreme st longitudinalwidth of the cover wing may be fromthree-fourths to approximately equal the slant'height of the V for the general form of structure shown in Fig. 4:, and this same dimension may be reduced to one half of the slant height of the V for the general form of structure shown in Fig. 1. Here, however, the length of the lower portion of the V extended to the rear of the cover should be proportioned according to the longitudinal width of the cover, if this extendedportion is relied upon to secure directional and longitudinal stability without the aid of a rudder and an elevator. The extended portion equal in length to'one and one half to twice the width of the cover, has

given good results. The height of the extended portion of. the V is also important, and may .be between fifty and seventy per cent. of the height of the V. In the general form of stru tur'e shown in Figs. 4 and 5, directional stability is obtained by the keel 7 extending backward and below the honzon'tal projection of the bottom of the V, and the elevator, or an elevator plane, WhlOll the real elevator is attached, is relled upon to secure longitudinalstability. 4

An appreciable arching in the cover wing over the center of gravity 'of the load carried seems to be -very desirable. This may be obtained either by making the cover wing a rigid arch, or by making the cover wing essentially a plane with suflicient flexibility so that when subjected to its normal load in flight, it will become appropriatelyarched.

thesides of the V sup orting it,'seems-to be desirable. The proba le explanation of this is that the flexible construction forms a kind of shock absorber when struck by a gust of.

windthe form of the structure is such that can cause, tendsto sharpen the V, 2'. 0., to decrease the angle of the V, and, therefore, to increase its stability, in so far as shape is Appreciable flexibility in both the cover and pract1cally.any deformation which the wind important; furthermore, thisflexible construction permits the main wing structure, when struck by a sudden gust of wind on one side to'swa sidewise with reference to the load carri and thus the main wing structure tends to reach a position of equilibrium without abruptly changin the direction of motionof the load carri Lateral or sidewise flexibility relative to a longitudinal axis passing through or near the center of gravity. of the load-carried is the desirable .consideration here. Longitudinal stability is secured by proper proportioning of the wing or elevator surface secured .in the rear of. the covered V as already pointed out. 7 In fact, it should be clearl appreciated that any considerable longitu inal flexibility, instead of increasing herent stability. This lateral flexibility in conjunction with longitudinal rigidity may be easily obtained with the simple plate-like construction for all wing surfaces as clearly indicated in the drawings. For example, in a'small model the wings may be cardboard or similar material, without struts, stays or cross-wires of any kind. In lar er models similar plate-like material, 0 suitable will tend to destroy inweight and strength, maybe used with a longitudinal web of the same material near the center, or this web mayhave an elastic. portion as herembefore set forth. It is com-Q mon knowled e thata plate-like structure .cannot be rea ily flexed or deflected relative axes at the same time;

to two intersectin and furthermore, t at the greater theflexure relative to one axis, the greater the difliculty of initiating flexure relative to a second and intersecting axis; especially is'this true if the second axis is approximately at a right angle with the first. Therefore, any curvature or arching of a plate-like Whig-structure about a longitudinal axis ten s to increase the longitudinal rigidity of saidwing structure. These thin, late-hke wing structures, assembled insuc manner that thick stiffening beams, struts, stays [and cross-- I wlres may be eliminated, reduce the drift a or head resistance to a minimum. Therefore, this'aeroplane structure is admirably adapted to attain very high speeds, as well as being inherently stable. It should be clearly appreclated, however, if efficient action at of this invention, a degree 'of elasticity is usual ly implied.- The more inclusive term 1 is generally used, however because, the

' wings m'iglht 3 not be sufficiently' elastic to return who to their original position after bein deflected, without being forced back by t action of the air in the opposite direction, and yet be sufliciently sluggish in vibratory movement to prevent fluttering. A fabric such as is commonly used in the constructionof kites, if extending loosely between supports, may flutter, because, between one extreme position and the other,

: there is no inherent resistance to travel ,as

ports fixed at a definitedistance apart, may

. extreme position to the wind pressure alternates in direction. In other words, it vibr tes rapidly from one e other. A. lively elastic .material, if stretched between supalso vibrate rapidly under favorable conditions, because the velocity attained, while moving from one extrem position to the middle, or neutral position, is suflicient to carry it well beyond the neutral position on the opposite side. On the other hand, a

sluggishly elastic material extending between fixed supports may be adapted to prevent fluttering, and otherwise fulfil r uire- 1 ments of this invention.- In general, ow-

ever, I prefer the self-supportingbplate-like structureas illustrated and descr1 ed. This structure is extremely simple; its flexibilityas a whole' is increased, inasmuch as the points of support'for'the cover wing are not fixed relative to the center of gravity of the load carried'-;;:'and besides, with this form of 1 structure,. I' believe it is possible to use a more lively l'elasticmaterial without danger of 'flutte p It shoi il d be evident, to one skilled in the art,-that this general form of structure combined with the tendency to automatically adjust itself to. the stresses sustained in differentparts of the structure, permits a kind of automatic camber while in flight, and also,

introduces new possibilities in maneuvering, etc.,- but the detailed setting forth "of these things belongs to an argumentative discus: sion relatingto the advantages of the invention, rather than to the disclosure of its fundamental structural characteristics.

.' In use, the gliding torpedo may be secured 111 any convenient manner, beneathan aeroplane, so that it can be suddenly and freely released by the aviator, after being.

carriedto any desired altitude. When the aviator sights the desired objective and has secured a favorable position, he may steer his aeroplane directly toward the objective, and div'm somewhat at the same time, at high speefi, he may release the torpedo, which 1s adapted to dive still more rapidly until it acquires a prodigious speed, when it will automatically take a more nearly horizontal course as indicated by the brokenline in Fig. 6. The aviator, meanwhile, may slow down his aeroplane, and when the tor pedo appears some distance infront of him, if his aeroplane and the torpedo are properly equipped with wireless directing mechanism, he may steer the torpedo precisely into the desired objective, because, if he keeps-the torpedo directly in his line of vision when looking at the Objective, he must register a, sure hit without any exact estimate of its distance away. Moreover, the-- torpedo may carry a depth bomb, and this directly beneath the waterline, as indicated in Fig.- 6, may destroy the most heavily armored battleship. The effectiveness of this gliding torpedo against submarines, ammunition depots, etc., should be evident.

This invention has been illustrated and described primarily with reference to its adaptation as a gliding torpedo, but its fundamental characteristics are, -by no means, confined to thisuse. It makes possible a flyin projectile; it may be positively propelled, hus ma g a flying torpedo, in

contradistinction to a gliding torpedo; it'

may be used as an improved parachute; and indeed, may be incorporated in aeroplane deslgn in a most general and inclusive sense.

The adaptation of the self-stabilizing aeroplane structure herein disclosed, is con-. templated for use in an aerial torpedo dis- H; g diial closed'and claimed in my co-pending cation for patent for aerial torpedo, No. 248,301, filed August 5, 1918. I ,claim.: a

, 1. In a self-stabilizing aeroplane structure, a V-wing arrangement in combination with a cover win attached directly to the cover wing terminating ti sof the V, sai

at either end substantially at its junction with the tips of the V,' and less extensive wing-like structure being attached in therear of SaidV-Wing arrangement, whereby longitudinal stability is secured, while still permitting the covered V-wing portion to predominate in the structure as a whole.

' '2. Ina self-stabilizing aeroplane struc ture,-a. V-wing arrangement in combination with a' cover wing attached to the tips of the V, and said cover wing being constructed and arranged to-prevent fluttering.

3. In a self-stabilizing aeroplane structure, a V-w-ing arrangement in combination with a cover wing attached to the tips of the V, said cover wing being constructed to have appreciabl inherent resistance to flexure combined with sufficient flexibility to permit a substantial u Ward deflection while carrying its normal oad in flight, whereby flexure without fluttering is obtained.

4. Ina self-stabilizing aeroplane structure, a V-wing arrangement in combination with a cover wing attached to the tips of the V, said. cover wing being sufliciently elastic to rise and fall gradually as the stresses in said cover-wing increase and decrease while in 5. In a self-stabilizing aeroplane structure, a V-wingarrangement in combination with; a cover wing attached to the tips of the V, the sides of said V having appreciable whole, when struck by a gust of wind from I one side, and said-mam wing structure .being adapted and arranged to prevent fluttering.

7. In a selfstabilizing aeroplane struc ture, a V-wing arrangement in combination with a cover wing attached to the tips of the V, and a longitudinal web extending the middle portion of the V to the middle portion of the cover, adapted to strengthen the structure, said web being sufficiently flexible to permit sidewise deflection. v

8. In a self-stabilizing aeroplane structure, a V-Wing arrangement in combination with a cover wing attached to the tips of the V, and a longitudinal web extending from the middle ortion of the V to. the middle portion of the cover, adapted to strengthen the structure, said web being sufliciently elastic to permit the middle portion of the from signature. i

MERLV R.'-' wonFARD.

cover wing to rise when subjected to an abnormal upward pressure.

9. In a self-stabil'zing aeroplane structure, a V-wing arrangement in combination with a cover wing attached to the tips of the -V, and means to yieldablysu-pport the middle portion of said cover wing.

10. In a self-stabilizing aeroplane structure, a V-wing arrangement in combination with a cover wing attached to the tips of the V, the lower portion of the V being extended to the rear-of the said cover wing, and the height of this extended portion of the V being less than three-fourths oftheheight of that portion of the V to the tips of which the said cover wing is attached.

11. In a self-stabilizing aeroplane struc ture, a .V-wing arrangement in combination with a cover wing attachedto the tips of the V, the lower rt on of the V extended to the rear 0 said cover wing, the height of this extended portion 'of the V being less than three-fourths of the height of that por-. tion of the V to the tips of which the said cover wing is attached, and longitudinal side keels secured to the sides of the V, substantially as illustrated.

I 12. In a self-stabilizing aeroplane structure, a V-wing arrangement in combination with a cover wing attached to the of the V, and an elevator, the lower portion of the V being extended to the rear of said cover v wing, and longitudinal side keels secured to the sides of the V, said keels being adapted ito support the elevator, substantially as illustrated. I

13. In a self-stabilizing aeroplane structure, a V-wing arrangement in combination with a cover wing attached to the tips of the V, said cover wing beingearched in form, the altitude of said 'arch ing less than onefourth of the linear distance from one end of the cover wing to the other, and cover.

wing being constructed and adapted to prevent fluttering.

In testimony whereof I have my 

